Lighting control systems must dynamically initialize, manage, and control the lumen level of luminaires as they set up light scenes and manage them in space and time. Current large lighting control systems are typically digitally networked systems that address luminaires individually and allow remote management of the individual luminaires via network access. Such lighting control systems are typically integrated as subsystems into building management systems.
For purposes of this disclosure, a lighting control system or network means one or more devices or systems, and/or an associated method(s), for, without limitation, installed/installing light sources, maintained/maintaining light sources, and/or controlled/controlling lighting schemes. Further, for purposes of this disclosure, “luminaire” means, without limitation, an electric light unit that may include, for example, one or more light-emitting diodes (LEDs) or other light source(s), electric ballasts, and/or a diming device, driver or controller.
In addition, for purposes of this disclosure, a “driver” is generally and without limitation a device or system that controls illumination of a luminaire—such as a dimming Visual Light Communication (VLC)/Dark Light Communication (DLC) control interface—but may also refer to any component that actuates a device, system, or method consistent with this disclosure.
Moreover, for purposes of this disclosure, the phrases “devices,” “systems,” and “methods” may be used either individually or in any combination referring without limitation to disclosed components, grouping, arrangements, steps, functions, or processes. For example, a lighting control system or network may include at least one of an electrical ballast, a luminaire including a light source such as an LED, a gateway for controlling illumination of the light source, and a dimming control interface to execute dimming commands for the light source. The dimmer controls must support specific interfaces to be able to receive control inputs and dim the light appropriately.
LEDs in particular have become regular light sources for use in luminaires particularly because LEDs do not fail abruptly like light sources such as incandescent or fluorescent bulbs. Instead, the lumen level (light output) of an LED slowly diminishes over time. Thus, a luminaire may be attached to a plurality of sensors that monitor the degradation of the luminaire as part of the lighting system maintenance and control. Certain sensors may measure, for example and without limitation, the lumen level, color content, color intensity, etc. of the luminaire at various dimming levels. The sensors may also include environment sensors to detect, among other things, ambient light, electrical and magnetic fields, temperature, motion, footfall (i.e., the number of people passing through or present in a given environment), and other aspects of the environment in which the luminaire is installed. For purposes of this disclosure, “environment” means generally and without limitation a space in which a luminaire or lighting device is installed.
Current lighting systems may include sensors which are located in close proximity with luminaires/light sources and are therefore directly exposed to light with potentially high luminous intensity coming out of the luminaires. Further, the electrical emissions around the luminaires can impact close proximity sensors. Luminaires with different lumen electrical emission impacts light sensing, environmental sensing, low resolution camera sensors, and other components and functions of the sensor systems. To avoid many of these problems, current sensor systems are custom designed to fit specific luminaires by shape and considering the electrical and lumen emissions. Thus, the current process for designing compatible sensor systems is not dynamic—i.e., a single sensor or sensor subsystem may not necessarily work with a replacement luminaire that is required during the life of the lighting system.
In addition, typical sensors used in lighting systems are sensitive instruments and high luminous intensities can easily overload and damage the sensor capacities and components. High lumen levels encountered by the sensor(s) can also create erroneous readings leading to inaccuracies in the collected data. Furthermore, some filters such as, among other things an Integrated Infrared (IR) filter that is used with the sensor can also be degraded by high lumen levels, leading to a lower lifetime of the sensor and/or filter.
Regarding communication of information between sensors and other components within lighting systems, one potential method is Visual Light Communication (VLC)/Dark Light Communication (DLC). VLC refers to communication using light signals in the visible light bandwidth while DLC refers to communication using light signals in the non-visible light bandwidth. VLC has the particularly beneficial capability to use the same illumination source for communication and illuminating the environment in which it is installed. In addition, the replacement of many florescent lamps with LEDs in the lighting industry makes VLC useful as a communication method for at least the reasons explained below.
For example, VLC has certain benefits over communication methods such as Radio Frequency (RF) communication because of the VLC's high bandwidth and immunity to interference from electromagnetic sources. VLC uses a light source that is frequency modulated, i.e., turned on and off rapidly when transmitting a communication. VLC systems communicate with visible light that occupies the spectrum from 380 nm to 750 nm corresponding to a frequency spectrum of 430 THz to 790 THz. Thus, VLC has a larger bandwidth compared to the bandwidth of radio frequency signals in RF communications. In addition, VLC may have certain security benefits compared to RF signals which may be intercepted and/or decoded from remote locations. Further, a visible light source may be used for both illumination and communication which conserves power that would be required to drive separate systems such as RF communications.
In view of the above, there is a need for devices, systems, and methods for enhancing, among other things, lighting system installation, maintenance, and control with VLC-based transmitters and receivers. In addition, there is a need for devices, systems, and methods that use VLC-based transmitters and receivers to identify luminaires in a lighting system, including the relative distance and direction of a visual-light transmitting luminaire to a VLC receiver. There is also a need for lighting system sensors that are configured to provide information about the light sources and their environment while being adaptable to installation in various locations and shielded from high levels of exposure to light.